TY - RPRT TI - Simulation of ground-water flow in the lower sand unit of the Potomac-Raritan-Magothy aquifer system, Philadelphia, Pennsylvania AU - R. A. Sloto PY - 1988 DO - 10.3133/wri864055 UR - https://pubs.usgs.gov/publication/wri864055 ID - wri864055 ER -